Paris-based Syrian academic Burhan Ghalioun, accompanied by a leading opposition figure Ahmed Ramadan (R), gives his address during a meeting in Istanbul October 2. Syria's main opposition groups agreed on Sunday to join a newly formed National Council, giving a major boost to President Bashar al-Assad's opponents.

The unification of Syria's largely leaderless opposition movement is almost certain to improve coordination with the international community, whose backing could add crucial momentum to the seven-month uprising. Until now, Western leaders have been unable or unwilling to provide the kind of support that could help the opposition overthrow Mr. Assad, the Washington Post reports.

Western diplomats have frequently identified the lack of a unified opposition movement as one of the Syrian uprising’s biggest obstacles. Without a coherent opposition or any clear sense of who or what would replace Assad, world powers and many ordinary Syrians have been reluctant to throw their weight behind efforts to unseat him, fearful of a power vacuum in the strategically located nation.

"The fact that Islamists, secular figures and activists on the ground are now on one council is a significant," a diplomat in the Syrian capital Damascus said.

"But they still have to demonstrate that they could be politically savvy and able to fill any political vacuum. They need a detailed action plan beyond the generalities of wanting a democratic Syria."

While the council dismissed any foreign intervention that would "compromise Syrian sovereignty," it said in its opening statement that the international community had a humanitarian obligation to protect Syrians, Reuters reports. The council also said that it wanted the uprising to remain nonviolent but that the Syrian regime's brutal crackdown was driving the country "to the edge of civil war and inviting foreign interference."

But while the opposition is united in their view that Assad must go, they reflect the divisions of Syrian society, which is made up of a variety of religious sects, ethnicities, and a range of political views from Islamism to secularism.

The Washington Post reports that the council is still divided on many critical issues, such as foreign intervention and whether to arm the uprising. While protesters are increasingly supportive of NATO assistance, many exiled opposition figures remain opposed to any foreign interference. Radwan Ziadeh, a Washington-based dissident on the council, said the decision on whether to call for foreign intervention "will be the most difficult decision for the council to take."

One of the hopes of the council is that now that the international community has a body to talk to, action against Assad will gain strength and momentum. France has already expressed public support for the council, although the US and Turkey have not, Reuters notes.

In an analysis piece for Foreign Policy last month, Kate Seelye writes that Washington has been explicit that the lack of a figurehead of the opposition has been a key hurdle to its assistance – and that the opposition is overcoming not just ideological differences, but a lack of understanding of how to compromise because of their lack of experience with dissenting opinions.

The disarray in the anti-Assad camp is recognized all too well in Washington. "I think the [international] pressure requires an organized opposition, and there isn't one," saidSecretary of State Hillary Clinton, when asked on Aug. 11 why the United States didn't throw more weight behind the protest movement. "There's no address for the opposition. There is no place that any of us who wish to assist can go."